ecosystems

Question 1

succession definition

Answer 1

a series of changes that occur to an environment and its’ organisms present in the area over time

Question 2

niche definition

Answer 2

an organisms role and interaction within its ecosystem

Question 3

biomass definition

Answer 3

amount of material produced by an organism which can be transferred as energy

Question 4

humus definition

Answer 4

dead organic matter from plants/animals death and secretion

Question 5

pioneer plants

Answer 5

first plants to appear in succession, their growth and death adds humus, retaining water, heat and nutrients

Question 6

2 differences between primary and secondary succession

Answer 6

• primary is new land, secondary is previously inhabited land that has been destroyed
• secondary is faster

Question 7

competitive exclusion principle

Answer 7

idea that 2 species occupying an identical niche cannot coexist indefinitely due to competition for food/shelter/minerals etc

Question 8

climax community

Answer 8

the result of succession when a community becomes stable. is called a plagioclimax when formed through human intervention

Question 9

what are 2 biotic factors

Answer 9

intraspecific and interspecific competition

Question 10

intraspecific

Answer 10

competition between members of the same species

Question 11

interspecific

Answer 11

competition between members of different species

Question 12

what are prey predator oscillations

Answer 12

prey causes predators ⬆️
when predators ⬆️ prey ⬇️
prey ⬇️ so predators ⬇️ and the cycle repeats

Question 13

what are abiotic factors

Answer 13

non living

Question 14

climate factors

Answer 14

light temp and humidity

Question 15

edaphic factors

Answer 15

ph, soil temp and texture

Question 16

topography

Answer 16

the gradient and 02 concentration in ponds

Question 17

how to measure as estimate of temperature changes

Answer 17

with temperature proxies such as the hockey stick graph

Question 18

why is there yearly fluctuations of CO2

Answer 18

• natural temp
• energy used
• time of year = photosynthesis

Question 19

why is methane dangerous

Answer 19

• more potent than CO2
• breaks down into carbon and water vapour

Question 20

how to estimate population size with grids

Answer 20

mean density per quadrant X total area
/
area of each quadrant

Question 21

how to use ice cores in estimating temp

Answer 21

analyse air trapped in layers as 02 isotopes reflect temp

Question 22

using radiocarbon dating in estimating tempt

Answer 22

• carbon isotopes
• peat bogs with the plants and pollen grains to understand climate lived in

Question 23

impact of climate change: rainfall

Answer 23

• warm air traps more water vapour
• causing droughts or flooding

Question 24

impact of climate change: ice melting

Answer 24

• sea levels rising
• water temps rise
• changes enzyme activity, animals may migrate
• land can be out underwater

Question 25

impact of climate change: enzyme activity

Answer 25

- can cause infertility - eggs may not hatch due to metabolic rate being too high/low

Question 26

impact of climate change: species distribution

Answer 26

other countries then have ideal temperatures for other animals causing migration - problem in insects as increases transmission of insect bourne disease

Question 27

how farming affects ecosystems

Answer 27

-crops removed and burned = less recycling of nitrogen, more carbon in air - monocultures deplete minerals in soil - artificial fertilisers = don’t support humus and soil structure (drainage etc)

Question 28

how fishing affects ecosystems

Answer 28

- too many fish caught, can’t repopulate esp if in breeding season - large nets can accidentally kill wrong species, can destroy habitats

Question 29

3 appendices of CITES

Answer 29

i - trade of organisms banned ii - animals at risk (extinction and endangerment) have grads controlled iii - trade is only regulated in specific regions

Question 30

what are losses in energy transfers

Answer 30

muscle movement and metabolic reactions (heat) faeces (undigested food) respiration

Question 31

problems with number pyramids to represent ecosystems

Answer 31

- hard to estimate - organisms are diff sizes - organisms have diff life cycles

Question 32

problems with biomass pyramids to represent ecosystems

Answer 32

- must be killed for dry biomass - time consuming - different components have different energy levels

Question 33

gross primary productivity

Answer 33

total light energy fixed by photosynthesis - plants use 25% for own needs

Question 34

net primary productivity

Answer 34

energy available for the next organism, relies on biotic and abiotic factors

Question 35

role of buffer strips

Answer 35

- contain diff species to increase biodiversity and provide protection - combats affect of monocultures depleting resources

Question 36

trophic levels

Answer 36

number of times energy has been transferred

Question 37

detrivores

Answer 37

ingest deed organic material

Question 38

saphrotrophs

Answer 38

- secrete defective enzymes and digest products

Question 39

what does nitrifying bacteria do

Answer 39

oxidises ammonium compounds to form nitrates

Question 40

role of nitrogen fixing bacteria

Answer 40

in soil or root nodules converts nitrogen into ammonia

Question 41

denitrifying bacteria

Answer 41

breaks down nitrates for production of ATP (NADP) and releases nitrogen gas as waste

Question 42

role of lightning in nitrogen cycle

Answer 42

when it strikes it transfers nitrogen from air to soil

Question 43

how is carbon removed from air and water

Answer 43

photosynthesis of plants and algae

Question 44

transfer of carbon in living things

Answer 44

through respiration, feeding, death and excretion

Question 45

role of fossilisation in carbon cycle

Answer 45

- traps carbon in fossil fuels - released via combustion

Question 46

role of sedimentation in carbon cycle

Answer 46

- carbonate rocks - released with weathering and volcanic activity

Question 47

how efficiency of energy changes in different trophic levels

Answer 47

- different animals use different amounts of energy - energy is lost in animals via faeces, heat loss and respiration - not all of animals are consumed

Question 48

role of fungi in ecosystems

Answer 48

are decomposes that crate more biological humus and aid in nutrient and nitrogen recycling